This invention relates generally to the navigation of a moving vehicle. In particular, this invention relates to a method and system for decreasing the maneuver proximity diameter to increase performance of a low cost server-based waypoint navigation system.
With the many advances that have been made in vehicle navigation over the last few years, there still exists the challenge to design facilities (equipment and methods) that are reliable, speedy and most important, accurate. As the equipment technology continues to evolve, new methods of determining information such as, position, speed, bearing and expected time of arrival are also evolving.
One of these methods is xe2x80x9cwaypoint navigation,xe2x80x9d where points are used to guide a vehicle in motion. Waypoints may represent electronic addresses that have been predetermined and used as milestones for vehicles navigating along a specific route. The waypoints on a route can be for example, a starting position, a destination position, and various maneuver points that present directional instruction (i.e., turn right, go straight, etc.). As a vehicle is navigating along a path, and as it approaches a waypoint, the navigation system can automatically calculate the distance and bearing to a predetermined position, for example, the next maneuver point.
Because the longitudinal and latitudinal profile of this previously determined position is known, distance and bearing information with respect to this position can be continuously calculated and monitored as a vehicle passes through waypoints on route to this position. These waypoints may provide indication that the navigating vehicle is in close proximity to a maneuver point. Depending on the distance calculation to a maneuver proximity area and to the center area of maneuver point position, determination can be made whether the vehicle has passed a maneuver point and is approaching the proximity area of the next maneuver point on an planned route.
Often, the proximity area associated with a predetermined position is located too close to the proximity area of a next predetermined position and can cause inaccuracies, or at a minimum, can increase the complexity of navigation position information processing. This increase in complexity can cause an increase in time required to process navigation information and may warrant additional computing resources, which may cause an increase in operating costs.
It would be desirable therefore to provide a method that overcomes the above disadvantages and provides more effective and timely navigation instructions to a moving vehicle.
One aspect of the present invention provides a method for generating navigation instructions for a vehicle. It may be determined whether a first proximity area associated with a first maneuver point overlaps with a second maneuver proximity area associated with a second maneuver point. It may also be determined whether a first vehicle location is within the first proximity area. A first distance between a first vehicle location and a zero point associated with the first maneuver point may be determined and a second distance between a second vehicle location and the zero point associated with the first maneuver point may be determined. The first proximity area may be truncated based on a comparison of the first distance and the second distance.
Another aspect of the present invention provides a system for generating navigation instructions for a vehicle. The system may include means for determining whether a first proximity area associated with a first maneuver point overlaps with a second maneuver proximity area associated with a second maneuver point and means for determining whether a first vehicle location is within the first proximity area. It may also include means for determining a first distance between the first vehicle location and a zero point associated with the first maneuver point and means for determining a second distance between a second vehicle location and the zero point associated with the first maneuver point. It may also include means for truncating the first proximity area based on a comparison of the first distance and the second distance
Another aspect of the present invention provides a computer usable medium including a program for generating navigation instructions for a vehicle. The program may include computer readable program code that determines whether a first proximity area associated with a first maneuver point overlaps with a second maneuver proximity area associated with a second maneuver point and computer readable program code that determines whether a first vehicle location is within the first proximity area. It may also include computer readable program code that determines a first distance between the first vehicle location and a zero point associated with the first maneuver point and computer readable program code that determines a second distance between a second vehicle location and the zero point associated with the first maneuver point. It may also include computer readable program code that truncates the first proximity area based on a comparison of the first distance and the second distance.